Projectile fuze



May 31, 1960 R. E. WENCKER 2,938,462

v PROJECTILE FUZE Filed April 20, 1956 PROJECTILE FUZE Filed Apr. 20,1956, Ser. No. 580,431

2 Claims. (Cl. 10271) This invention relates to projectile fuzes andmore particularly to such fuzes provided with means for selfdestructionof the fuze and projectile at a desired time interval after theprojectile has been fired.

The ordinary type of projectile fuze is designed so that it will beinitiated upon impact and in addition a number of such fuzes areprovided with various types of devices to insure self-destruction of thefuze and projectile in the event that it fails to contact the target.This self-destruction feature is particularly important in projectilesused in air-to-air weapons for if the fuzes of such projectiles are notprovided with some means for exploding the shell in the air they willexplode upon contact with the ground, possibly in friendly territory.Although various types of self-destruction devices for fuzes have beenheretofore employed, all of them have been of a very intricate natureand dependent upon precision mechanisms and exceedingly closetolerances. Such devices have generally depended upon centrifugal forceand spin decay of the projectile, upon complex clocking mechanisms, orexternal propellers. Other such devices have relied upon the airpressure generated by the travel of the projectile or upon differentialsbetween such pressures and the pressure in a sealed aneroidal container.While Various types of such self-destruction elements functionsatisfactorily they leave much to be desired in ease of manufacture,economy and capability to function in a foolproof manner under allconditions.

It is therefore an object of this invention toV provide aself-destruction projectile fuze that overcomes the disadvantages of theprior art. Another object of this invention is to provide a novelprojectile fuze having selfdestroying means that become operable uponset-back. Another object of this invention is to provide a novel meansfor the automatic destruction of a projectile at a desired time intervalafter it has been fired.

The manner in which these and other objects are accomplished by thisinvention will be fully understood when the following descriptionthereof is read in connection with the drawing in which- Figure 1 is afragmentary view particularly in section illustrating a fuze made inaccordance with this invention in position in a projectile; and

Figure 2 is a similar view illustrating another embodiment of thisinvention Y In accordance with this invention, generally stated, theseand other objects are accomplished by providing a fuze containing a gasfilled or gas producing capsule that is activated upon set-back when theprojectile is fired in the gun, and after a desired time interval thegas builds up suihcient pressure to drive the tiring pin into the detonator, thus destroying the shell. More specifically, these objects areaccomplished by providing an impact detonating fuze comprising aforwardly located gas filled or gas producing capsule, a firing pin inthe form of a cap for a cavity housing the capsule, and having a pointextending forwardly so as to puncture the capsule when the inertia ofthe capsule forces it rearwardly upon set-back. Upon 2,938,462 PatentedMay 3l, 1960 tiring of the projectile, the forces of set-back cause thecapsule to be punctured, and gas leakage or generation from the capsuleinto the surrounding container after a period of time blows the firingpin cap off the container and into the detonator. Thus, the iiring pinof the present invention is provided with two oppositely disposedpoints, one of which is designed to contact the detonator and the otherof which is designed to puncture the capsule upon set-back. Preferably,the tiring pin serves as a botton closure of a container which surroundsthe capsule of compressed gas, but if this portion of the fuze isairtight the external container for the capsule can be eliminated.

Any type of relatively inert gas can be used as the motivating means forthe self-destruction element of this invention. Thus, carbon dioxide,nitrogen, oxygen and any other commercially available inert compressedgas can be used in this capacity. Alternatively, the capsule can befilled with a material capable of producing gas upon penetration of theforward point of the tiring pin. For example, the capsule can be filledwith an acid such as hydrochloric and the cavity surroundings thecapsule lined with a coating of zinc or the like. Likewise, the capsulecan serve as a reservoir for an acid, such las hydrochloric or aceticsurrounded by a solution of sodium bicarbonate or, if preferred, thesodium bicarbonate solution can surround a capsule of acid. Means mustbe provided to prevent penetration of the capsule prior to the time theprojectile is red from the gun. In order to prevent such prematurepenetration of the capsule it can be held in a position away from theforward firing pin by means of a spring or the like. Prematurepenetration of the capsule by the forward point of the tiring pin canalso be avoided by crimping or staking the capsule in a position remotefrom the firing pin. Also, in order to prevent detonation of the maincharge of the projectile upon set-back, means which do not form a partof the present invention are provided to prevent the tiring pin fromimpinging on the detonator.

In order that the invention may be further clarified and more fullyunderstood, the following is a detail description of a preferredembodiment thereof.

As shown in Figure 1 of the drawing, the tiring pin is a two-pieceelement, the lower portion 1 forming a base and closure for thecylindrical portion 2. In this embodiment a gas tight seal between thetwo portions of the firing pin is provided by crimping the cylindricalportion into the base portion as shown at 6. It will be readilyappreciated however that the seal can also be effected by swaging andsimilar operations or by use of adhesives andV sealants. The cylindricalportion ofthe firing pin serves as a reservoir for acid 18, such asacetic or hydrochloric in volume 7 and also as a container for a capsule3 containing a solution of sodium bicarbonate 17 or the like. The baseportion of the tiring pin is provided with a rearwardly directed point 4adapted for penetration of the detonator and an oppositely directedpoint 5 which penetrates the capsule 3 upon exertion of the set-backforces upon firing of the projectile. In this embodiment the capsule ismaintained in a position remote from the forward point of the tiring pinby three indentations 16 in the cylindrical portion of the firing pin.If desired, these indentations can be replaced by a circumferentialcrimp. This crimp or indentation permits normal handling of theprojectile during manufacture and transportation, but the capsule isforced past the crimp by the forces exerted upon set-back and isperforated by the forward point of the ring pin.

Figure 2 of the drawing shows a tiring pin in accordance with thisinvention in position in a typical projectile fuze. In this example thecapsule 3 is charged with compressed gas 17, such as carbon dioxide,rather than a gasw n generating composition and is surrounded by air.The firing pin shown in this embodiment is of thev same generalconfiguration as the one shown in Figure l but it will be noted that thelower portion, of the firing pin Ais provided with a flange 8 extendingupwardly to receive the lowersegment 9 of the cylindrical portion 2 ofthe ring pin. These two `portions of the firing pin form a tightfrictional fit which is gasproof but can be broken by the exertion oflongitudinal pressure. This firing pin assembly also differs somewhatfrom that shown in Figure 1 in that the forward point 5 of the firingpin is surrounded by a helical spring V10.A This spring is equivalent tothe retaining indentations referred to in connection with the embodimentset forth in Figure 1 of the drawing.. It will, however, be readilyappreciated that any other device will be equally satisfactory toprevent premature contact between the capsule3 andthe point 5 of thering pin. Y

In this figure the firing pin assembly is positioned in the longitudinalaxial bore 11 of a fuze body 12 and the cap of the fuze is shown at 13.Premature penetration of point '4 of the firing pin into the detonator14 is prevented by the protruding centrifugally responsive dogs whichare illustrated diagrammatically at 15. These dogs do not form a part ofthe present invention and any other suitable means can be provided toprevent the rearward motion of the firing pin assembly prior to impactupon the objective of the projectile.

Operation As shown in Figure 2 the fuze assembly is in condition to befired from a gun. When the propellent charge of the projectile is firedthe set-back forces overcome the inertia of the gas filled capsule 3,thus depressing the restraining spring and permitting the forward point5 of the tiring pin to penetrate the base of the capsule. This causesthe gas contained within this capsule to escape into the cylindricalportion 2 of the tiring pin assembly. Rearward travel of the entire ringpin assembly upon set-back is prevented by dogs 15 or. by any otherequivalent retarding means that are retracted by centrifugal force whilethe projectile is in flight. After such restraining means have beenretracted from the bore 11, the base of the firing pin is then in aposition to be driven into the detonator uponV the application of forcewhich can be derived either upon impact of the projectile with thetarget or by the gas pressure released due to the perforation of thecapsule 3. In the event that the of the ring pin assembly.

however that this pointcan be of a .tapered or stepped configuration andthat in such instances the size of the perforation `in the capsule willbe dependent at least to a degree uponY the forces exerted uponset-back. Thus, the time interval between the firing of the gun and theactuation of the self-destroying'means of this invention can beshortened by providing a higher initial pressure in the capsule 3, byincreasing the diameter of the forwardly directed penetrating point ofthe firing pin or by reducing the strength of the bond between the twosegments of the tiring pin.y Conversely, this time interval projectiledoes not meet thetarget, Vthe gas escaping from the capsule into thechamber 7 gradually increases the pressure therein and finally reachesaV level sufficiently high to break the `seal between the base 1 of thefiring pin and the cylindrical portion 2. When this seal is broken thecylindrical portion of the firing pin is held relatively stationary bythe surrounding elements of the fuze and the major Vportion of the forcefrom the compressed gas is exerted on base portion 1 of the ring pinwhich is then driven downwardly into the detonator, initiating thecharge and destroying the entire. projectile.

The time interval between the ring of the projectile and the initiationof the self-destroying means of this invention is determined by theinitial pressure in the capsule, the size of the hole formed in the basethereof and can be lengthened by reducing thelgaspressure in` thecapsule, by utilizing a penetrating pin of smaller diameter, or byyproviding a relatively strong bond between the segments ofv theftiringpinV assembly. ByV coordinating these variables any desired timelinterval can be'obtained.

While the'preferred embodiment of the invention has been described, itis evident that. various modifications are possible without departingfrom the scope of the invention as expressed in the following claims.

What is claimed is:

l. A projectile fuze of theY impact myself-destroying type comprising adetonator, a fuze body having a longi-V tudinal bore in generalalignment with the detonator, a firing pin in said bore, means forVpreventing impact of. the firing pin on the detonator upon set-back,said tiring pin having two separable portions, the forward portion ofthe 4firing pin beingV a cylindrical member closed at its forward endand containinga capsule of compressed pask relatively free to movetherein and the other portion of the firing pin being a disc closing theposterior end of the cylindrical member and having a pair ofoppositelydisposed points, one adaptedto penetrate the capsule upon set-back andthe other adapted to penetrate the detonator. 2. A projectile fuze oftheimpact or self-destroying type comprising a detonator, a fuze bodyhaving a longi` tudinal bore in generalalignmentvwith the detonator, atiring pin in said bore, means for preventing impact of the firing pinon the detonator upon set-back, said firing pin havingtwo separableportions, the kforward portion of the firing pin lbeing a cylindricalmemberl closed at its forward Vend and containing a gas producingcapsule relatively free to move `therein and the other portion of thefiring pin being a disc closing the posterior end of the cylindricalmember and having a pair of` oppositely disposed points, one adaptedto,-p.enetrate the -capsule upon set-back and the other adapted topenetrate the detonator.

.References Cited in the file ofthis ypatent Y UNITED STATES PATENTS

